2-haloallyl nu-alkyl dithiocarbanilates for controlling undesirable vegetation



2,997,381 Z-HALOALLYL N-ALKYL DITHIOCARBANI- DATES FOR CONTROLLING UNDESIRABLE VEGETATION John J. DAmico, Nitro, W. Va., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed Apr. 1, 1958, Ser. No. 725,497 12 Claims. (Cl. 7 12.6)

formula S O %SCH2C=CH2 where R represents an alkyl group containing at least two carbon atoms and preferably less than five and X represents halogen. X is preferably a middle halogen but may be fluorine or iodine.

Several methods are available for making the compounds of this class. A procedure which has given good results involves the ammonium salt of the corresponding dithiocarbanilate with a 2-haloallyl halide. For example, 2-bromoallyl N-ethyl dithiocarbanilate was prepared as follows: Approximately 60.6 grams of N-ethylaniline was dissolved in 100 ml. of ethyl alcohol and 50 grams concentrated ammonium hydroxide. This solution was stirred While to it was added in one portion 50 grams carbon bisulfide. The reaction mixture was stirred at 25-30" C. for one hour. There was then added 77.7 grams of 2-bromoallyl chloride. The addition caused the temperature to rise from 28 to 45 C. The reaction mixture was then stirred at 2530 C. for 24 hours and then 400 ml. or water was added. After stirring for 15 minutes the reaction mixture was extracted with 400 ml. of ethyl ether and the ether extract washed with dilute hydrochloric acid until the aqueous layer did not yield any amine upon neutralization with 25% sodium hydroxide. The ether solution was then washed with water until neutral to litmus and dried over sodium sulfate. The ether was removed in vacuo at a maximum temperature of 80-90 C. at 1-2 mm. There was obtained 109 grams (69.1% yield) of Z-bromoallyl N-ethyldithiocarbanilate as an amber oil. It contained 4.1% nitrogen as compared to 4.4% nitrogen calculated. The properties of other typical examples of the new toxicants prepared in similar manner are summarized below.

Patented Aug. 22, 1961 1 free Table l Analysis Compound Physical Appearance Calcd. Found i Percent N- 5. 2 5. 1 2-Ohloroallyl N-ethyldisolid mp. P

. v 1 O crcent S. 23. 6 23. 3 thiocarbanilate. .4042 0 Percent O1" 0 13. 1 2- Ohloroallyl N-butyl.-. amber oil- Percent N- 4. 7 4. 7

dithiocarbanilate. 2- Ohloroallyl N -hexyl- Percent N. 4. 3 4. 3

dithiocarbanilate. 2-Ohloroallyl N-propyl- Percent N. 4. 9 4. 9

dithiocarbanilate. 2-Ohloroallyl N-isopro- Percent N. 4. 9 4. 2

yldithiocarbanilate. 2- hloroallyl N-isobutyl- Percent N. 4. f7 4. 3

dithiocarbanilate.

The toxicants of this invention are valuable as grassspecific herbicides. They are toxic to grass foliage. The compounds where R in the general formula above is ethyl or a branched chain alkyl group of 3 or 4 carbon atoms are particularly valuable as pro-emergent grassspecific herbicides. Useful results are achieved by b1inging the toxicants in contact with growing plants by which is meant application to the soil before the plants emerge whereby the toxicant is brought into contact with germinating seedlings or application to foliage after emergence.

The toxicant may be applied conveniently in the form of a spray containing the active ingredient within the range of 0.1%5%.' For pre-emergence application amounts within the range of 1 to 60 pounds per acre are recommended. The active components are insoluble in Water but they are soluble in common organic solvents. They may be dispersed directly in water or dissolved first in an organic solvent and then dispersed. As dispersing and wetting agents there may be employed soft or hard sodium or potassium soaps, alkylated aromatic sodium sulfonates Such as sodium dodecylbenzenesulfonate, or an amine salt of dodecylbenzenesulfonic acid, alkali metal salts of sulfated fatty alcohols, ethylene oxide condensation products of alkyl phenols or tall oil and other dispersing and Wetting'agents. The herbicides may be formulated and applied as'dry compositions by mixing the toxicant with a finely divided solid carrier, as for example talc, clay,.p yr0phyllite, silica and fullers earth. Alternatively, the dry composition may be dispersed in water and applied as a spray.

Table II illustrates the pre-ernergent herbicidal activity. In these tests the ester was emulsified in water and the emulsion applied as' a spray. The active. ingredient at the indicated dosage per acre was applied to the soil of seeded plots .before the grass or other plants emerged.

For convenience in recording the data a numerical rating system was used as follows:

0No phytotoxicity 1Slight phytotoxicity 2Moderate phytotoxicity 3Severe phytotoxicity The plants are represented in the table by letters as follows:

H. Cotton A. Morning glory B. Wild oats J. Corn C. Brome-cheat grass K. Foxtail D. Rye grass L. Barnyard grass E. Buckwheat Crab grass F. Radish-mustard N. Field bindweed G. Sugar-beet Pigweed I Tobie 11 Active Ingredient lbsJA A B O D E F G H J K L M N O I 25 1 a 2 1 0 2 2 0 2 3 3 0 a Z-Chloroallyl N-ethylphenyldithio- 5 0 2 2 2 0 (1 0 0 0 3 3 0 2 carhanilato. 2 0 1 1 2 0 0 0 0 0 2 3 t) 3 1 o 0 0 1 0 0 1 2 o a 3 o a 2-Chloroallyl N-isopropyldithiocarbanilate 25 1 1 1 0 0 1 0 2 0 2 a 0 3 Z-Chloroallyl N-lsobutyldithiocar- 7 bnnilate 25' 1 2 0 0- 0 0 1 0 0 1 3 0 3 2-Brolnoallyl N-ethyldithiocarbanilate Z5 0 2 1 1 0 0 0 0 0 3 2 3 0 3 Foliage tests were carried out by applying the toxicant If a phytotoxic effect on growing grasses of a compound as an aqueous spray to the tohage of grass, beans and to J of the struct a mixture of broad-leaf plants. Typical results are summarized below. Table 1?' O SCH, ?=GH2 R X Phytotoxieity Active Ingredient 532 2" 5 where R represents an alkyl group containing 2-4 carbon cent Grass Bean lBroadatoms and X represents halogen.

leaf 8. A herbicidal composition comprising a major pro- 7 I E portion of a carrier and a small amount sufficient to exert [L5 2 2 2 a phytotoxic eifect on growing grasses of a compound 2 Ohlor0ally1 N-bntyl-dithiocarbaniof the structure late 0.5 1 i 3 1 2-Ghloroallyl N-hexylrdithiocarbani- S dii nn'n id ot "WS I l 1 2 ll anLatin:.i gigfi;- g2 j g 3 g Q-o-soH,-o=o11: 2-Ohloroall l N-iso ropyit ocarbanilate p i 0.2 1 0 1 R x 2-Ohloroallyl N-isobutyl-dithiocarr bamlate 2 V 2 2 Where R represents a member of the group consisting of It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A method of controlling vegetation which comprises applying to foliage thereof a toxic concentration of a compound of the structure where R represents an alkyl group containing at least two but less than five carbon atoms and X represents halogen.

2. A method of controlling vegetation which comprises applying to germinating grass seedlings atoxi'c concentration of a compound of the structure where R represents a member of the group consisting of ethyl and a branched chain alkyl' radical containing less than 5 carbon atoms and X represents a member of the group consisting of chlorine andbromine,

3. A method of controlling vegetation which comprises applying to germinating seedlingsa toxic concentration of 2-chloroa1-1yl N-ethyldithiocarbanilate.

4. A method of controlling vegetation which comprises applying to germinating seedlings a toxic concentration of Z-bromoallyl N-ethyldithiocarbanilate.

5. A method of controlling vegetation which, comprises applying to germinating seedlings a toxic concentration of Z-chloroallyl N-isopropyldithiocarbanilate.

6. A method of controlling vegetation which comprises applying to the foliage thereof a toxic concentration of Z-chloroallyl N-butyldithiocarbonilate.

7. A herbicidal composition comprising a. major proportion of a carrier and a small amount sufiicient to exert ethyl and a branched chain alkyl radical containing less than 5 carbon atoms and X represents a member of the group consisting of chlorine and bromine.

9. A herbicidal composition comprising a major proportion of a carrier and a small amount sufficient to exert a phytotoxic eifect on growing grasses of 2-chloroallyl N-ethyldithiocarbanilate.

10. A herbicidal composition comprising a major proportion of a carrier and a small amount sufiicient to exert a phytotoxic efiect on growing grasses of 2-bromoallyl N-ethyldithiocarbanilate.

11. A herbicidal composition comprising a major proportion of a carrier and a small amount sufficient to exert a phytotoxic effect on growing grasses of 2-chloroallyl N-isopropyldithiocarbanilate.

12. A herbicidal composition comprising a major proportion of a carrier and a small amount sufficient to exert a phytotoxic effect on growing grasses of 2-chloroally1 N-butyldithiocarbanilate.

References Cited in the file of this patent UNITED STATES PATENTS Re. 22,750 Tisdale et a1. Apr. 30, 1946 2,127,375 Bousquet Aug. 16, 1938 2,535,877 Stewart Dec. 26, 1950 2,744,898 Harmon et al. May 8, 1956 2,766,554 Dorman- Oct. 16, 1956 2,854,467 Harmon et al. Sept. 30, 1958 2,863,899 Harris Dec. 9, 1958 2,895,980 Harmon et a1. July 21, 1959 FOREIGN PATENTS 858,352 Germany Dec. 4, 1952 205,460 Australia Jan. 16, 1957 OTHER REFERENCES Metcalf: Advances in Pest Control Research, publ. by Inter-science PubL, N.Y., 1957, pages 67 and 68.

Plant Regulators, page 27, CBCC Positive Data Series, No. 2, June 1955, Chemical-Biological Ccordina 18 tion Center. 1 

1. A METHOD CONTROLLING VEGETATION WHICH COMPRISES APPLYING TO FOLIAGE THEREOF A TOXIC CONCENTRATION OF A COMPOUND OF THE STRUCTURE 